Yondr, aimed at concert goers, is "form-fitting case" that slips over phones and locks the device during a show. I wonder when people will start using this for meetings?
Checky (from the makers of Calm, which I have enjoyed on a few zen workdays) tracks how many times you look at your phone throughout the day.
And Flic, which is less about managing addiction and more focused on the consequences. The tinder-style app helps users cull down the problematic piles of photos stored on phones.